Diarthrotarsus guianensis, Gil-Santana, 2022

Gil-Santana, Hélcio R., 2022, New records, taxonomic notes, and the description of a new species of Harpactorinae (Hemiptera: Heteroptera: Reduviidae) from French Guiana, Zootaxa 5105 (3), pp. 381-400 : 385-388

Diarthrotarsus guianensis sp. nov.

( Figs. 9–19 )

Diagnosis. Diarthrotarsus guianensis sp. nov. can be separated from other species of Diarthrotarsus by the absence of a pair of small spiniform protuberances located close to posterior margin of hind lobe of pronotum, between the humeral angles, which are observed in all other species of the genus. The new species shares with D. malaisei and D. marahuacensis the absence of tubercles behind ocelli, present in other species. However, the apex of the abdomen in dorsal view is deeply incised at its middle, forming a pair of very protruding lobes in D. malaisei ; presents a small median notch in D. marahuacensis , with lobes not prominent; while in D. guianensis sp. nov. it is truncate, with the distal margin straight in dorsal view. Additionally, the humeral spines of D. guianensis sp. nov. are quite larger than those of D. marahuacensis ; in the latter species the median portion of posterior margin of hind lobe of pronotum is curved, slightly concave, while in D. guianensis sp. nov. it is straight; the corium of hemelytra is stramineous with a reddish tinge in D. marahuacensis and generally brownish in D. guianensis sp. nov. Diarthrotarsus malaisei and D. guianensis sp. nov. are separated by the head which is somewhat longer (neck included) than double of its width across eyes in the former species and it is just two times as long as wide across eyes in the latter; distal portion of hind lobe of pronotum, just below the level of the humeral spines to the posterior margin, and scutellum pale orange to yellowish in D. guianensis sp. nov. and uniformly pale brownish in D. malaisei .

Description. Female. MEASUREMENTS: total length: to tip of abdomen 10.6; to tip of hemelytra 10.3; head: length: (excluding neck) 1.6; (including neck) 2.0; length of anteocular portion 0.6; length of postocular portion 0.5; width across eyes: 1.0; minimum dorsal interocular distance (synthlipsis) 0.5; width of eye 0.2; length of eye 0.4; height of eye 0.5; distance between external margins of ocelli 0.6; distance between ocelli 0.3; maximum width of ocellus 0.1; distance between postantennal spines bases 0.5, between postantennal spines apices 0.7; lengths of antennal segments: I 2.4; II 1.8; III–IV absent; lengths of labial segments: II [first visible] 1.0; III 0.6; IV 0.5. Thorax: pronotum: fore lobe: length at dorsal midline 0.9; maximum width 1.3; hind lobe: length at dorsal midline 1.3; maximum width 2.7; scutellum: width at basis 0.7, length 0.7. Fore legs: length of femur 2.9, maximum width 0.8; length of tibia 2.5; length of tarsus 0.4; middle legs: length of femur 2.5, maximum width at midportion 0.3, width at subapical portion 0.35; length of tibia 2.6; tarsus absent; hind legs: length of femur 2.9, maximum width at midportion 0.2, width at subapical portion 0.3; length of tibia 3.7; tarsus absent. Abdomen: length 5.7; maximum width 2.6. COLORATION. General coloration brownish with darkened and pale portions ( Figs. 9–10 ). Head ( Figs. 9–12 ): dark brownish to brownish black; a somewhat paler, brownish dorsal elongated rectangular glabrous and smooth area on midline; tip of postantennal spines paler; labium generally pale, last segment darkened with a subtle reddish tinge ventrally and at lateral and dorsal surfaces of approximately distal half; antennal scape generally pale with base, a large median ring and apex darkened; pedicel pale yellowish with base shortly and apex, more extensively, darkened; flagellomeres absent. Thorax ( Figs. 9–10, 13 ): brownish; distal portion of hind lobe of pronotum, just below level of the humeral spines to posterior margin, and scutellum pale orange to yellowish; stridulitrum pale, prosternum posterior to fore coxae, meso- and metasternum pale yellowish; hemelytra generally brownish; clavus pale at approximately basal half; corium somewhat paler above inner third of membrane, apex darkened, blackish. Legs ( Figs. 9–10, 14–16 ): coxae and trochanters pale with irregular scattered markings with reddish tinge; fore coxae somewhat darkened around base. Fore femur generally dark, pale basally and at submedian distal portion, without forming a complete annulus at latter position, because dorsal surface and ventral crest are darkened at this portion; the pale coloration is more extensive on posterior surface and has a reddish tinge, while in its anterior surface there is a thin reddish curved line at approximately median portion of the pale marking. Middle and hind femora and tibiae generally pale; middle and hind femora each with submedian basal and apical (except distal margin) dark annuli, latter larger than the former, dorsobasal portion with a small faint dark marking, and a faint narrow reddish line between submedian and apical annuli; tibiae with dark submedian basal and distal annuli and apices, former annuli larger than the latter, extreme base variably darkened too; a narrow faint annulus between base and submedian basal annulus, which may be interrupted or imperceptible in some tibiae; hind tibia with a reddish marking, on outer surface, contiguous to posterior margin of submedian distal dark annulus. Fore tarsi (others absent): first segment pale, second segment and claws reddish brown. Abdomen generally dark brownish ( Figs. 9–10, 17 ). Connexival segments pale orange at approximately distal third, except last segment where the pale orange coloration extends to approximately the distal two thirds ( Fig. 9, 17 ). First five visible sternites, except lateral portions, mostly pale; remaining segments, including genitalia, darkened ( Fig. 10 ). STRUCTURE: Head ( Figs. 9–12 ): elongated, 1.6 times as long as wide across eyes (length measured excluding neck), shorter than pronotum (including neck); anteocular portion with subparallel margins in dorsal view, slightly longer and narrower than postocular portion; latter, in dorsal view, narrowing gradually to form a neck; minimum distance between eyes in dorsal view (synthlipsis) almost three times longer than width of each eye; integument mostly granulated; clypeus small, straight in dorsal view, rounded in lateral view, slightly elevated; antennifers close to apex of head, not prominent; scape elongated, somewhat curved, longer than head and pedicel, latter straight, thinner than scape, both antennomeres cylindrical and slightly thickened at apex, flagellomeres absent; postantennal spines short, acute, obliquely diverging forward; vertex somewhat elevated; eyes glabrous, not prominent, rounded in dorsal view, subhemispherical in lateral view with posterior margin somewhat concave, reaching dorsal outline of head at interocular sulcus, not reaching ventral margin of head, which is near inferior margin of eye; transverse sulcus deep, straight, curved laterally, reaching inner posterior third of eye; a small elongated thin fossa present immediately anteriad of transversal sulcus; just anterior to this fossa, also on midline, an elongated rectangular glabrous and smooth area, about twice longer and broader than fossa; ocelli slightly prominent, small, rounded, closer to eyes than to each other, distance between them more than twice diameter of each ocelli; tubercles behind ocelli absent; labium stout, curved, thickened; segment II (first visible) thickest, almost straight, reaching level between middle and posterior third of eyes, approximately 1.6 times as long as segment III, which is somewhat curved; segment IV shortest, narrowest, curved, tapering, reaching prosternum at approximately its midportion. Thorax ( Figs. 9–10, 13 ): integument generally intensively granulated. Pronotum: collar shallow; anterolateral angles rounded, small; fore lobe subsquared in dorsal view, somewhat shorter and narrower than hind lobe; submedian and sublateral granulated, ill defined, shallow carinae on distal portion of fore lobe, surpassing transverse furrow and reaching basal portion of hind lobe for a short distance; smooth and glabrous areas between and above them; midlongitudinal sulcus very shallow and thin, present only on distal third of fore lobe, interrupted above transverse furrow by a triangular elevated portion; transverse furrow curved, shallow. Hind lobe widening towards humeral angles, which have large spiniform processes directed laterally; distally to them, margins narrow towards posterior margin, latter straight at median portion and with sublateral and lateral angles, former larger and rounded, latter smaller and subtriangular. Supracoxal lobes of propleura slightly prominent, others not; stridulitrum large; posterior portion of fore acetabula closed. Legs ( Figs. 9–10, 14– 16 ): fore coxae very close; middle and hind coxae distant from each other by a distance slightly less than width and half of width of each of them, respectively. Fore trochanters with a short crest, more elevated subapically, with short setae and granules. Femora and tibia progressively less granulose than thorax, granules more numerous on fore femora and darkened portions of segments. Fore femora very thickened and enlarged, narrowed on ventral midline, where there is a crest which is split in two curved branches at basal portion of segment with posterior branch more prominent; remaining of crest is straight and becomes shallower towards apex of femur, ending before distal margin by a distance equivalent to half of width of femur in that portion; between distal margin of femur and tibia a large membranous area with a pair of elongated sclerotizations united apically by a narrow sclerotized band. Middle and hind femora generally straight, slightly dilated subapically. Tibiae, on lateral view, curved at distal third, fore tibiae more so and middle least curved; all compressed latero-laterally, becoming progressively thinner towards apex, but not at latter, which is enlarged; fore tibiae with a spur and a mesal comb on inner surface; a small pad on apices of all tibiae. Fore tarsi two-segmented; other absent. Scutellum carinate, lateral margin curved; apex rounded; postscutellum globose; both with smooth integument. Hemelytra generally dull, not reaching apex of abdomen; rectangular cell of corium elongated, curved; cells of membrane short, basal one subtriangular, distal one subrectangular Abdomen ( Figs. 9–10, 17–19 ): suboval in shape in dorsal and ventral views; connexivum with margin uniform, without prominences; apex truncate in dorsal view; sternites with integument smooth and shiny, with thin linear shallow transverse impressions; intersegmentar sutures thin and curved. External female genitalia as in Figs. 18–19 . VESTITURE. Body integument generally covered by very small, sparse, short, thin pale setae, in some portions almost imperceptible. Head: dorsal elongated rectangular smooth area on midline glabrous; eyes glabrous; antenna: scape with sparse thin short setae and a few longer elements at apex; pedicel covered by a pubescence of short, curved, thin, pale setae, which are more numerous and long at apex of segment; flagellomeres absent. Labium with a few pale short to slightly longer pale straight to somewhat oblique setae, sparsely distributed on segments II and III. Thorax: smooth areas between and above carinae of fore lobe glabrous. Coxa and trochanters with scattered stout pale setae, more numerous on ventral surface and short crest of fore trochanters; some isolated longer curved setae on fore coxa. Femora with small, short, thin, adpressed setae and scattered few larger, stout, curved setae; ventral crest of fore femur is covered by numerous short, erect setae, which are somewhat larger on basal branches. Fore and middle tibiae with a ventromedial fringe of short, erect setae, except on basal portion of segments. All tibiae with apex surrounded by numerous longer straight pale setae. Hemelytra glabrous. Abdomen covered by sparse, adpressed, short, thin, pale setae.

Distribution. French Guiana.

Etymology. The specific epithet guianensis is derived from French Guiana, where the species was collected, with the Latin adjectival suffix “-ensis”, meaning “pertaining to” or “originating in”.

Type material. FRENCH GUIANA. Female holotype: Bélizon, xi.1997, leg. H. Gaspard, ( MNRJ) .

A key to the species of Diarthrotarsus is presented below.

Figures

FIGURES 9–19. Diarthrotarsus guianensis sp. nov., female holotype. 9–10, scale bar 2.0 mm, 9, dorsal view, 10, ventral view; 11–13, scale bar 1.0 mm; 11–12, head, 11, dorsal view, 12, lateral view; 13, distal portion of head, and thorax, dorsal view; 14–19, scale bar 0.5 mm; 14–16, lateral view, 14, fore femur, posterior surface; 15–16, fore tibia, 15, anterior surface, 16, posterior surface; 17, apex of hemelytra and abdomen, dorsal view; 18–19, apex of abdomen, schematic outline, 18, lateral view, 19, ventral view.